Anti-jackknifing apparatus has been provided in many configurations. U.S. Pat. Nos. 2,962,301, 3,837,678 and 3,972,542 illustrate the use of a fluid operated cylinder for moving an abutment means between a position within the longitudinal slot in the fifth wheel and a position remote from the slot. Such devices, however, provide limited maneuverability to make turns such as are required on mountainous roads or when maneuvering within the truck docking area. A major problem is making it possible to remove the abutment means for the slot when it is desired to do so. In devices of the type having cylinder operating abutment means, binding between the parts makes it impossible to withdraw the abutment means, and due to the mounting of the cylinder limited support is provided so that the cylinder becomes readily dislodged and the apparatus consequently becomes inoperable.
Accordingly, it is an important object of the invention to provide a sturdy mounting for the cylinder and movable parts affording support therefor during operation while facilitating withdrawal from the fifth wheel when such becomes necessary.
Another important object of the invention is the provision of a mounting for an abutment means within the slot of the fifth wheel in such a way that the angular disposition between the tractor and the trailer when the abutment means engage the sides of the slot may be adjusted to accommodate the terrain over which the tractor is to travel.